Flow characteristics of continuous shear drawing of high carbon steel

Abstract

Equal channel angular drawing (ECAD) is a method to obtain the material with large plastic deformation in a continuous way. While flow instability tends to occur at the exit channel during the ECAD, the shear drawing (SD) process might be an alternative technique that secures stable flow and continuous process at the same time. The aim of the present work is to develop the SD process, which prevents flow instability of the ECAD and imposes a high plastic deformation on the material. For this purpose, the multi-pass SD process consisting of the die intersection angle of 150 degrees was designed by the finite element analysis. For verification of the designed process, experiments were carried out with commercially available high carbon steel. Experimental results showed that the newly designed SD process improved flow stability and roundness of the specimens compared to the conventional ECAD. Compression and hardness tests were made to investigate mechanical property of the specimen. Scanning electron microscopy was employed to check changes of the microstructure. The results of SEM indicated that the original cementite lamellae were fragmented into short and distorted segments. Additional numerical study was carried out to investigate flow characteristics and distribution of the effective strain with varied die intersecting angles. According to the present investigation it was found out that the effective strain value and flow instability increased by decreasing the intersecting angle. (C) 2011 Elsevier Ltd. All rights reserved.